The overall objective of this study is to contribute to the understanding of what factors determine health status, focusing in particular on the relative importance of personal characteristics, disease history, and use or non-use of various types of health care delivery systems and their services. The analytic objective will be to develop a multi-variate causal model of health status which represents the structural relationships underlying the many factors affecting health status. This model will be developed incrementally in "blocks" of related factors, where each block represents a major research approach to the explanation of health status. This allows different sources of variation in health status to be explored independently and at the same time facilitates comparison of the contribution of each separate focus to health status. The model will consist of a set of recursive linear equations for each block which will form a recursive system that can be analyzed by regression methods. The data to be utilized will be drawn from the Institute of Medicine's study of pediatric care in Washington, D.C., which consists of a household survey, a survey of providers, and an independent clinical examination of children. Health status will be represented by three selected medical conditions -- otitis media and associated hearing loss, vision defects, and iron deficiency anemia. This model will indicate which types of factors are most important in affecting health status conditions, and will allow identification of the degree to which "policy" variables (i.e., ones subject to policy manipulation such as the utilization patterns of patients and health screening procedures of physicians) may significantly affect health status. Further, the study may point out those data parameters which might be relevant to quality "outcome" reviews by bodies such as PSROs.